Various parts of Piper obliquum Ruiz & Pavon yielded the new alkenylphenols obliquol A (1) and obliquol B (2), the new 4-chromanone 3 together with the known compounds 4 and 5. A synthesis of obliquol B (2) was developed in order to confirm its structure and to provide sufficient amounts for biological testing. Compounds 1 and 2 have antibacterial activity comparable to that of ampicillin, 2 in addition possesses potent anti-NF-kappa B activity by targeting early events in the TNF alpha-induced NF-kappa B inflammatory pathway, which may explain the effects reported for the traditional use of the plant. (C) 2008 Elsevier Ltd. All rights reserved.
Development of an Efficient Synthesis of <i>rac</i>
-3-Demethoxyerythratidinone via a Titanium(III) Catalyzed Imine-Nitrile Coupling
作者:Hieu-Trinh Luu、Jan Streuff
DOI:10.1002/ejoc.201801479
日期:2019.1.10
The development of an efficient synthesis of the erythrinaalkaloid 3‐demethoxyerythratidinone is described. A titanium(III) catalyzed umpolung in form of an imine–nitrile coupling reaction serves as key step for the construction of the highlighted C–C bond.
A Telluride-Triggered Nucleophilic Ring Opening of Monoactivated Cyclopropanes<sup>1</sup>
作者:Dmitry V. Avilov、Mahesh G. Malusare、Engin Arslancan、Donald C. Dittmer
DOI:10.1021/ol0492804
日期:2004.6.1
[reaction: see text] Acylcyclopropanemethanol tosylates undergo rapid ringopening at room temperature by the action of lithium telluride to produce the enolate of a homoallylic ketone. The enolate can be protonated to yield the corresponding ketone or treated with benzaldehyde to give the aldol product with good syn or anti diastereoselectivity depending on the conditions.
A Pd0complex can mediate dehydrogenative formation of 2,4-diene systems from γ,δ-unsaturated carbonyls in the presence of 2,6-DMBQ (2,6-dimethyl-1,4-benzoquinone), which undergo vinylogous addition to imines via auto-tandem Pd0-π-Lewis base catalysis. Both chemically inverse δ-regioselective aza-Morita–Baylis–Hillman adducts and α-regioselective normal ones are obtained switchably and stereoselectively
Synthesis of 1,2,4,5-tetra-substituted benzenes via copper-catalyzed dimerization of γ,δ-unsaturated ketones
作者:Kai-Xian Ma、Chuan-Ming Hong、Jiang-Min Yan、Qing-Hua Li、Tang-Lin Liu
DOI:10.1039/d4cc02458c
日期:——
An efficient cyclization for the synthesis of 1,2,4,5-tetra-substituted benzenes via copper catalyzed dimerization of γ,δ-unsaturated ketones has been described. This one-pot procedure employs the γ,δ-unsaturated ketones as the sole substrate with multiple C–C bond formation. This protocol features broad substrate scope and provides a facile and robust method to construct polysubstituted benzene derivatives